Thin film lithium niobate modulators at 1064 NM for CMOS-compatible systems
Date
2021
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Publisher
University of Delaware
Abstract
Across the world, the telecommunications industry has deployed numerous systems for rapid transmission of data across long distances, including cell phone and internet networks. Photonic technologies and fiber-optic communications are ubiquitous in these systems because they allow for lower loss and greater energy efficiency than a conventional electrical transmission line. One photonic device that is crucial to these systems is the electro-optic modulator, which converts signals from the electrical domain to the optical domain at high speed. ☐ Lithium niobate is the material of choice for electro-optic modulators and many such devices have been demonstrated, in bulk lithium niobate at 1550 nm and 1064 nm, as well as thin-film-lithium-niobate (TFLN) at 1550 nm. This thesis presents the first analysis of electro-optic modulators in thin-film-lithium-niobate at shorter wavelengths, especially 1064 nm. Since the half-wave voltage (Vπ) is proportional to the wavelength, a modulator at 1064 nm has the notable advantage of a lower Vπ compared to a similar modulator at 1550 nm. Another significant advantage can be identified when considering the modulator as a component in a larger photonic system, such as an analog photonic link system or an imaging system. In such a system, the modulator would be used in conjunction with light-sensing components (photodetectors and/or image sensors). At 1550 nm, the light-sensing components must be made of III-V semiconductor materials, which are more expensive. However, a system implemented at 1064 nm can use silicon light-sensing components, which are available at lower cost and are CMOS-compatible. Thus, the modulators presented in this thesis open the door towards photonic systems in which the overall cost is reduced.
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Keywords
Lithium niobate, Microfabrication, Modulators, Optics, Photonics, Silicon nitride